British Telecom (BT) is working on a plan to eliminate the keyboard and mouse, and use accelerometers with tablet PCs instead.

The pilot project enables a user to scroll through menus or applications simply by tilting or rotating the tablet PC. The system starts with a specially designed adapter containing tiny accelerometers, which measure acceleration. The adapter plugs into any tablet PC via a USB cable. When a user moves the PC, the sensors detect the motion. Special software then interprets the PC’s movements and translates them onto the computer screen.

“What we want to create is a kind of broadband Etch A Sketch,” says BT researcher David Chatting, who wrote the applications for the prototype.

The trick, he says, is getting people sensitized to how moving the PC affects what happens on the computer. “One of my initial applications entails using the PC to manipulate a marble on the screen. I want to demonstrate to the user that how they’re holding the device affects what’s happening–that they have an almost physical connection to the content on the screen.”

For now, Chatting’s applications are simple. A user moves the machine left or right to toggle between a few menu choices on-screen, and then pulls the machine forward to select a menu item. “We aren’t trying to duplicate all [of] Windows Vista or Mac OSX,” Chatting says.

But he is convinced that software could be further adapted so that a person could, say, turn the pages of a virtual book just by tilting the machine, or even move a cursor around a Web page and then click on a link just by giving the machine a light shake.

“The technology has obvious implications for those who are disabled or elderly and [have] difficulty using a fiddly laptop keyboard or mouse,” says Adam Oliver, head of BT’s Age and Disability Research Program, of which BT Balance is a part. “We wanted to create an interface that was simple and intuitive. Standard ways of controlling PC applications can be too complicated.”

Accelerometers are used in a wide range of devices. In the Nintendo Wii hand controller, they provide the raw data from your body’s movements that end up as on-screen actions. They also help stabilize the image on your camcorder. Typically, these accelerometers are so small that they fit into a class of devices known as microelectromechanical systems (MEMS).

BT is hardly the first company to put a MEMS accelerometer into portable electronic equipment. Nike and Apple, for example, have teamed up on a product called the iPod Sport Kit. An accelerometer placed in a special pair of Nike running shoes measures workout data, then wirelessly transmits the information to an iPod Nano.

Some tablet PCs and PDAs even feature an option that allows the screen’s content to be viewed right-side up, no matter which way the device is held.

Many laptops sold today include a motion-sensing chip that can detect when the machine is falling, and then automatically protect the data on the hard disk from any damage caused by the fall.

But what BT is trying to do–make an affordable computer that can effectively interface with a user only through moving the machine–is trickier. “The motion-sensing tablet PC is a lovely idea,” says Jan Korvink, a MEMS expert at the University of Freiburg, in Germany. “But you’ll have to deal first of all with drift.”

“Drift” is what happens when microsensors, whether through being continuously overheated or by picking up noise signals, degrade over time. “You have to continuously adjust for drift,” Korvink says. “And cheap sensors–the kind you need to mass-produce electronics–tend to drift a lot.”

According to Korvink, an even bigger issue is finding the “killer applications” for a motion-sensing PC. That will require, he says, a lot of research into what users might want to employ such a device for, and then tweaking the software to make it extremely user-friendly.

With the Chumby computer, a coffee-cup-size Internet appliance designed to display basic information downloaded from the Internet, users will be able to create their own applications that enlist the computer’s built-in accelerometers for input. “The real question is how many Flash developers remember enough of their Newtonian physics to use this sensor effectively,” says Chumby software guru Duane Maxwell.

Maxwell also says that the company itself has experimented with writing software that would allow the Chumby device to be used to scroll through RSS feeds just by tilting it.

But BT’s Chatting says he is well aware that his work is far from being ready for commercial use. “Just like in the 1970s, [when] we were trying to figure out what we could do with a mouse, there’s a lot of learning that needs to be done here.” Chatting is hoping to put together a real field trial soon so that he can begin to get feedback on how people might actually use a motion-sensing tablet PC.